Masteries

Offense:
3

Defense:
6

Utility:
21

Introduction

So here's my build for Zilean. I always played this build and I've always been a good teammate to others, be it in support or aggresive ap( depends which path the game takes).

Runes

For runes i take magic penetration(gives your bombs that hit you need), armor and mr for survivability( believe me it really makes a difference) and a little bit of ap in quints( you can change that for whatever you like be it survivability but DON'T take cooldown reduction)

Masteries

Masteries are simple support build with armor and mr, nothing really to explain there, you want better mana regen, more mana and some cd to help you spam those bombs in the beggining

Items

So for starters i take meki pendant, always. Doran will slow your build a lot so i don't recommend it because you won't deal that much dmg in beggining. Having clarity and teleport make you agile enough around the map and your time warp gives your teammate and your speed when on lane. After that rush tear and boots. Spam your skills to use passive of Tear( believe me that will be in 10 mins from buying it if you do it sucessfully). You can teleport your way back or just use spells to boost your mana, either way works, but don't waste your tp. After that take Ionia boots for cd 15% and go for glacial shroud (needed for cd and survivability). You should have about 36% cd now and you can spam your skills like crazy if your rewind is high. Now you have to take catalyst for more survivability during laning/ganking or just tping to your allies to help them. After that finish archangel, veil and other items i recommended. Rylai is for slowing your enemies with bombs and gives you hp and more ap for reviving and dmg dealing. GA is just to annoy your enemies if they do manage to kill you somehow, either way works but getting ga is your last concern.

Skill Sequence

Simple, you star with a bomb, take rewind and time warp. You max your bomb first, then rewind and then time warp(ofcourse take ults on 6,11,16).

Summoner Spells

Well summoner spells speak for them self. As zilean you're very mana dependant and having your skills take a lot of mana( 100 and more) you need it A LOT! clarity will give you that extra mana you need to revive yourself or your teammate or even give you speed boost either way it helps you live or to kill someone. Live and let die!
Teleport? Somebody laughs at the mention of it on zilean. Well he doesn't need ghost or flash, cause he has his speed boost, if they still get to you, you got your ult and a second chance to run or kill. Other summoner spells didn't really go good with him :/

Team Work

When laning be sure to hit the squishies with bombs so your allies can kill them easily. Also be sure to give that speed boost a lot when needed. Having your ult up all the time is crucial in team fights. I usually have it up in about 20 secs from activating hence making my enemies pissed of. If you're building rylais you slow your enemies for your allies or even yourself if you're a badass. Remember, Zilean without a team is nobody, so this build depends heavily on the fact you won't have ******s that solo their way into their tower with 5 enemy champs. Watch out when using your ult cause it wears out fast. Other then that spam your skills like crazy and your teammates will laugh with you when the other team fails at killing anybody for full 15 or more minutes

Creeping / Jungling

I had to put it, so here it is. During my play with Zilean, it's hard to get creeps in the beggining cause of mana regen/mana and bomb mana use. Rush tear so you can get more mana and mana regen and cooldown reduction really makes a difference. Put a bomb on one creep, hit it with your primary attack while you rewind and put another bomb on him again to make double bomb explosion. Kills every minnion around, so creeping after tear is really not that hard at all.

Pros / Cons

Pros
+High survivability
+excellent support
+lots and lots of mana
+slowing down enemies/speeding up your allies
+reviving every 20 secs
Cons
-rough start
-depends on your team
-i couldn't find any more cons for this build

Summary

So to sum up, during my gameplay of LoL i've seen a lot of Zilean builds and here also, but none of them worked for me. Why? I don't know maybe i'm just noobish to understand them but this build worked every time for me even if our team lost at the end i had excellent scores. If i play zilean i get at least 12 assists per game or more. My record with him was 12/2/23 and i daily get scores like 7/2/15 or more, depends how you play and on your team, if there are better damage dealers then i just get assists, either way we win and my team laughs at their pathetic atempts to kill us. Getting so many friend requests is really troubling at the end. I hope you like my build and it helps you play Zilean the way he should be played, OP:D